Pattern Formation Method

ABSTRACT

A pattern formation method includes forming a first pattern in a first film in a first region and forming a second pattern in the first film in a second region by using an optical lithography technology. The pattern formation method also includes forming a third pattern corresponding to the first pattern in a second film below the first film in the first region by using a self-organization lithography technology. The pattern formation method also includes transferring the third pattern to a third film below the first film and the second film in the first region and transferring the second pattern to the third film in the second region.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Japanese PatentApplication No. 2017-056499, filed Mar. 22, 2017, the entire contents ofwhich are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a pattern formationmethod.

BACKGROUND

By using a self-organization lithography technology, predeterminedpatterns are formed on a substrate. In this case, it is desired toefficiently form the patterns.

DESCRIPTION OF THE DRAWINGS

FIG. 1A, FIG. 1B and FIG. 1C are process sectional views illustrating apattern formation method according to some embodiments.

FIG. 2A, FIG. 2B and FIG. 2C are process sectional views illustrating apattern formation method according to some embodiments.

FIG. 3A, FIG. 3B and FIG. 3C are process sectional views illustrating apattern formation method according to some embodiments.

FIG. 4A and FIG. 4B are process sectional views illustrating a patternformation method according to some embodiments.

FIG. 5A and FIG. 5B are process sectional views illustrating a patternformation method according to some embodiments.

FIG. 6A, FIG. 6B and FIG. 6C are process sectional views illustrating apattern formation method according to a modification example of someembodiments.

FIG. 7A, FIG. 7B and FIG. 7C are process sectional views illustrating apattern formation method according to a modification example of someembodiments.

FIG. 8A, FIG. 8B and FIG. 8C are process sectional views illustrating apattern formation method according to a modification example of someembodiments.

FIG. 9A, FIG. 9B and FIG. 9C are process sectional views illustrating apattern formation method according to a modification example of someembodiments.

FIG. 10A and FIG. 10B are process sectional views illustrating a patternformation method according to a modification example of someembodiments.

DETAILED DESCRIPTION

An example embodiment provides a pattern formation method capable ofefficiently forming patterns by using a self-organization lithographytechnology.

In general, according to some embodiments, a pattern formation methodmay include forming a first pattern in a first film in a first regionand forming a second pattern in the first film in a second region byusing an optical lithography technology. The pattern formation methodmay include forming a third pattern corresponding to the first patternin a second film below the first film in the first region by using aself-organization lithography technology. The pattern formation methodmay include transferring the third pattern to a third film below thefirst film and the second film in the first region and transferring thesecond pattern to the third film in the second region.

In the following, with reference to the drawings, a pattern formationmethod according to example embodiments will be described in detail. Itis noted that the present disclosure is not limited to theseembodiments.

A pattern formation method according to some embodiments will bedescribed. The pattern formation method may include formingpredetermined patterns on a substrate. In some embodiments, in alithography technology for forming the predetermined patterns on thesubstrate, the patterns may be miniaturized.

As a lithography technology of a manufacturing process of asemiconductor element, a double patterning technology by ArF immersionexposure, EUV lithography, nanoimprint and the like can be used;however, some lithography technology may cause an increase in cost, areduction of throughput and the like with the miniaturization ofpatterns.

In such a situation, a self-organization (DSA: Directed Self-Assembly)material can be applied to the lithography technology. Theself-organization material (DSA material) can be organized by aspontaneous behavior for energy stabilization, so that it can be appliedto form a pattern with high dimensional accuracy.

For example, in a technology using microphase separation of a polymerblock copolymer, it is possible to form various shapes of periodicstructures of several nm (nanometers) to several hundreds of nm by acoating and annealing process. A shape may be changed to a sphericalshape (or a sphere), a columnar shape (or a cylinder), a layered shape(or a lamella) and the like by a composition ratio of blocks of apolymer block copolymer and a size may be changed by a molecular weight,so that it is possible to form various dimensions of dot patterns,holes, pillar patterns, line patterns and the like.

In order to form desired patterns in a wide range by using the DSAmaterial, it is possible to provide a guide for controlling a generationposition of a polymer phase formed by self-organization. The guide canbe a physical guide (e.g., grapho-epitaxy) having an uneven structureand forming a microphase separation pattern in a recess portion, or achemical guide (e.g., chemical-epitaxy) formed at a lower layer of theDSA material and controlling a formation position of a microphaseseparation pattern on the basis of a difference of surface energythereof.

For example, a resist film may be formed on a processed film, resist maybe exposed to form a hole pattern serving as a physical guide, and ablock copolymer (BCP) may be embedded in the physical guide and may beheated. Then, the BCP may be phase-separated (microphase-separated) intoa first polymer portion formed along a sidewall of a guide pattern, anda second polymer portion formed at a center of the guide pattern.Thereafter, the second polymer portion may be selectively removed andthe first polymer portion may be allowed to remain, a pattern (forexample, the hole pattern) having a dimension smaller than that of theguide pattern can be processed and transferred to a base film. This iscalled a DSA hole shrink process.

That is, when the guide pattern is formed with a dimension near aresolution limit in optical lithography, since a pattern (for example,the hole pattern) having a dimension smaller than the resolution limitcan be formed in the base film, a pattern can be miniaturized to besmaller than the resolution limit of the optical lithography.

However, in the DSA hole shrink process, since a hole diameter isdetermined based on a molecular weight of the BCP, it may be difficultto simultaneously form patterns (for example, a cell portion, aperipheral circuit and the like) with dimensions different from oneanother. Therefore, when a lithography process is provided to eachpattern, it is possible that the number of processes will easilyincrease and cost will increase.

In this regard, in some embodiments, pattern formation using theself-organization lithography technology may be performed and a part ofthe physical guide may be used for the pattern formation as is,resulting in a reduction of the number of processes required for formingpatterns with dimensions different from one another.

In some embodiments, as illustrated in FIG. 1A to FIG. 5B, predeterminedpatterns are formed on a substrate. FIG. 1A to FIG. 1C, FIG. 2A to FIG.2C, FIG. 3A to FIG. 3C, FIG. 4A and FIG. 4B, and FIG. 5A and FIG. 5B areprocess sectional views illustrating a pattern formation method,respectively.

In the process illustrated in FIG. 1A, a substrate 1 is prepared. Thesubstrate 1, for example, can be formed with a material in which asemiconductor such as silicon is a main component. The substrate 1 mayhave a region R1 and a region R2. The region R1 and the region R2 may beregions where patterns with different dimensions are to be formed. Theregion R1 may be a region where patterns with a dimension smaller thanthat of the region R2 are to be formed, and for example, maybe a cellregion where a fine pattern such as memory cells are disposed. Theregion R2 may be a region where patterns with a dimension larger thanthat of the region R1 are to be formed, and for example, may be aperipheral region where a peripheral circuit for the cell region isdisposed. In the region R1 and the region R2, a processed film 2, a hardmask 3, a hard mask 4, and a hard mask 5 may be sequentially depositedon the substrate 1.

For example, the processed film 2 can be formed with a material, inwhich silicon oxide is a main component, by a CVD (Chemical VaporDeposition) method, a spin coating method and the like. When theprocessed film 2 is formed by the spin coating method, the processedfilm 2 can also be called a SOG (Spin On Glass) film. The processed film2 can be formed with a thickness of 150 nm. The hard mask 3 can beformed with a material, in which carbon is a main component, by the CVDmethod, the spin coating method and the like. When the hard mask 3 isformed by the spin coating method, the hard mask 3 can also be called aSOC (Spin On Carbon) film. The hard mask 3 can be formed with athickness of 100 nm. The hard mask 4 can be formed with a material, inwhich silicon oxide is a main component, by the CVD method and the like.The hard mask 4 can be formed with a thickness of 15 nm. The hard mask 5can be formed with a material, in which silicon nitride is a maincomponent, by the CVD method and the like. The hard mask 5 can be formedwith a thickness of 15 nm.

In the process illustrated in FIG. 1B, a resist pattern RP1 selectivelycovering the part of the region R1 in the hard mask 5 may be formed.

For example, a resist material may be coated on the hard mask 5 by thespin coating method and the like. The resist material can be coated tobe a thickness of 1.5 μm. The resist material may be exposed anddeveloped by MUV (Middle Ultra Violet) light, so that a resist filmselectively remains on the region R1 and is selectively removed from theregion R1. In this way, the resist pattern RP1 selectively covering thepart of the region R1 in the hard mask 5 may be formed.

In the process illustrated in FIG. 1C, a hard mask 5 a for selectivelycovering the part of the region R1 in the hard mask 4 may be formed.

By the RIE, the hard mask 5 may be etched using the resist pattern RP1as a mask. In this way, the part of the region R1 in the hard mask 5 maybe selectively removed, so that the hard mask 5 a selectively coveringthe region R1 is formed.

In the process illustrated in FIG. 2A, on the hard mask 5 a and the hardmask 4, a hard mask 6, an antireflection film 7, and a resist patternRP2 may be formed.

For example, the hard mask 6 can be formed with a material, in whichcarbon is a main component, by the CVD method, the spin coating methodand the like. When the hard mask 6 is formed by the spin coating method,the hard mask 6 can also be called a SOC (Spin On Carbon) film. The hardmask 6 can be formed with a thickness of 100 nm. The antireflection film7 can be formed with a material, in which silicon oxide is amaincomponent, by the CVD method, the spin coating method and the like. Whenthe antireflection film 7 is formed by the spin coating method, theantireflection film 7 can also be called a SOG (Spin On Glass) film. Theantireflection film 7 can be formed with a thickness of 30 nm.

A resist material may be coated on the antireflection film 7 by the spincoating method and the like. The resist material can be coated to be athickness of 120 nm. The resist material may be exposed and developed byArF immersion excimer laser and the like, thereby forming a resistpattern RP2 having a hole pattern RP2 a in the region R1 and having ahole pattern RP2 b in the region R2. A maximum width of the hole patternRP2 a may be smaller than that of the hole pattern RP2 b. A diameter ofthe hole pattern RP2 a, for example, is 70 nm and a diameter of the holepattern RP2 b, for example, is 200 nm.

In this case, the hard mask 5 a may exist between a bottom surface(e.g., a surface of the antireflection film 7 exposed through the holepattern RP2 a) of the hole pattern RP2 a and the hard mask 4, but it ispossible that the hard mask 5 a does not exist between a bottom surface(e.g., a surface of the antireflection film 7 exposed through the holepattern RP2 b) of the hole pattern RP2 b and the hard mask 4.

In the process illustrated in FIG. 2B, the hole patterns RP2 a and RP2 bin the resist pattern RP2 may be transferred to an antireflection film 7a and a hard mask 6 a.

For example, by the RIE method and the like, the antireflection film 7may be etched using the resist pattern RP2 as a mask. In this way, thehole patterns RP2 a and RP2 b in the resist pattern RP2 may betransferred to the antireflection film 7 a. That is, in the region R1, ahole pattern 7 a 1 corresponding to the hole pattern RP2 a may be formedin the antireflection film 7 a, and in the region R2, a hole pattern 7 a2 corresponding to the hole pattern RP2 b may be formed in theantireflection film 7 a.

Then, by the RIE method and the like, the hard mask 6 a may be etchedusing the antireflection film 7 a as a mask. In this way, the holepatterns 7 a 1 and 7 a 2 in the antireflection film 7 a may betransferred to the hard mask 6 a. That is, in the region R1, a holepattern 6 a 1 corresponding to the hole pattern 7 a 1 may be formed inthe hard mask 6 a, and in the region R2, a hole pattern 6 a 2corresponding to the hole pattern 7 a 2 may be formed in the hard mask 6a. The formed recess patterns (e.g., the hole patterns 7 a 1 and 6 a 1and the hole patterns 7 a 2 and 6 a 2) may serve as physical guides of aself-organization pattern of a subsequent process.

In the process illustrated in FIG. 2C, in the physical guides (e.g., thehole patterns 7 a 1 and 6 a 1) of the region R1 and the physical guides(the hole patterns 7 a 2 and 6 a 2) of the region R2, self-organizationmaterials may be respectively embedded.

For example, the self-organization materials may be coated on theantireflection film 7 a and the hard mask 6 a. The self-organizationmaterial, for example, can use a block polymer. As the block polymer, ablock copolymer (PS-b-PMMA) of polystyrene (PS) and polymethylmethacrylate (PMMA) may be prepared and a number average molecularweight (Mn) of the PS block/the PMMA block may be allowed to be4,700/24,000. The block copolymer may be phase-separated in one verticalcylinder shape in a guide having a diameter of about 50 nm or more andabout 100 nm or less. This maybe molten by a propylene glycol monomethylether acetate (PGMEA) solution having a concentration of 1.0 wt %, sothat a PGMEA solution of a block copolymer is formed. Then, the PGMEAsolution of the block copolymer may be discharged onto the substrate 1while rotating the substrate 1 at a rotation speed of 1,500 rpm. Then,the substrate 1 may be rotated at a rotation speed of 1,000 rpm for 30seconds and may be subjected to spin drying so that a block copolymerfilm can be uniquely formed in the surface. In this way, a block polymerfilm 11 may be embedded in the hole patterns 7 a 1 and 6 a 1, and ablock polymer film 12 may be embedded in the hole patterns 7 a 2 and 6 a2.

In some embodiments, before the self-organization materials (e.g., theblock copolymers) are coated, a process for controlling contact anglesof the surfaces of the guide patterns (e.g., the hole patterns 7 a 1 and6 a 1 and the hole patterns 7 a 2 and 6 a 2) may be added. For example,a silane coupling agent may be supplied to the surfaces of the guidepatterns to reform lipophilicity, so that lipophilic polystyrene (PS)can be favorably coated in the guide patterns.

In the process illustrated in FIG. 3A, the block polymer film 11 in thehole patterns 7 a 1 and 6 a 1 and the block polymer film 12 in the holepatterns 7 a 2 and 6 a 2 may be respectively microphase-separated.

For example, the stacked body SLB obtained in the processes up to FIG.2C may be heated by a heating device, so that the block polymer film 11and the block polymer film 12 are respectively microphase-separated.When the stacked body SLB is heated on a hot plate at 240° C. for threeminutes, the block polymer film 11 and the block polymer film 12 can bemicrophase-separated.

In the hole patterns 7 a 1 and 6 a 1, a self-organization phase, whichincludes a first polymer portion 11 a including a first polymer blockchain and a second polymer portion 11 b including a second polymer blockchain, maybe formed. In this case, in the hole patterns 7 a 1 and 6 a 1,a regular pattern (a vertical cylinder shape) may be formed. At theinner surface sides of the hole patterns 7 a 1 and 6 a 1, the firstpolymer portion 11 a including the PS may be formed (e.g., segregated),and at the center sides of the hole patterns 7 a 1 and 6 a 1, the secondpolymer portion 11 b including the PMMA may be formed.

Similarly, in the hole patterns 7 a 2 and 6 a 2, a self-organizationphase, which includes a first polymer portion 12 a including a firstpolymer block chain and a second polymer portion 12 b including a secondpolymer block chain, may be formed. In this case, it is possible that inthe hole patterns 7 a 2 and 6 a 2, a regular pattern is not formed. Inthe hole patterns 7 a 2 and 6 a 2, the first polymer portion 12 aincluding the PS and the second polymer portion 12 b including the PMMAmay be randomly phase-separated. This is because maximum widths(diameters) of the hole patterns 7 a 2 and 6 a 2 deviate from the rangeof a guide diameter proper for phase separation of the regular pattern(the vertical cylinder shape) of the block copolymer.

In the process illustrated in FIG. 3B, a hole pattern 11 c may bedeveloped in the hole patterns 7 a 1 and 6 a 1 and a hole pattern 12 cmay be developed in the hole patterns 7 a 2 and 6 a 2.

For example, by the RIE method and the like, the block polymer film 11and the block polymer film 12 may be etched in an etching condition thatetch selectivity of the polymethyl methacrylate (PMMA) with respect tothe polystyrene (PS) can be ensured. In this way, in the hole patterns 7a 1 and 6 a 1, the first polymer portion 11 a may be allowed to remainand the second polymer portion 11 b is selectively removed, so that thehole pattern 11 c is formed. In the hole patterns 7 a 2 and 6 a 2, thefirst polymer portion 12 a may be allowed to remain and the secondpolymer portion 12 b is selectively removed, so that the hole pattern 12c is formed. The hole pattern 12 c may be formed as a dummy pattern.

For example, the hole pattern 11 c may have a vertical cylinder shapeand a diameter of 25 nm, and may correspond to a hole obtained bycontracting the hole patterns 7 a 1 and 6 a 1. A part of the surface ofthe hard mask 5 a may be exposed through the hole pattern 11 c. The holepattern 12 c may have a random shape. It is possible that the holepattern 12 c does not expose the surface of the hard mask 4.

In order to develop the hole patterns 11 c and 12 c, it is possible touse another method capable of selectively removing the second polymerportion, instead of the RIE method. For example, a development processor wet etching, in which the hole patterns 11 c and 12 c are exposed toIPA (isopropyl alcohol) or acetic acid after UV irradiation, may beused.

In the process illustrated in FIG. 3C, in the region R1, the holepattern 11 c may be transferred to the hard mask 5 b to form a holepattern 5 b 1, and in the region R2, it is possible that the holepattern 12 c (e.g., the dummy pattern) is not transferred.

For example, in the region R1, the hard mask 5 a may be etched by theRIE method and the like by using the remaining first polymer portion 11a and the antireflection film 7 a as a mask. Apart of the surface of thehard mask 5 a exposed through the hole pattern 11 c may be selectivelyremoved and the hole pattern 11 c is transferred to the hard mask 5 b,so that the hole pattern 5 b 1 is formed. A part of the surface of thehard mask 4 may be exposed through the hole pattern 5 b 1. In the regionR2, since the first polymer portion 12 a covers the hard mask 4, it ispossible that the hole pattern 12 c is not transferred to the hard mask4.

In the process illustrated in FIG. 4A, the first polymer portion 11 amay be removed from the inside of the hole patterns 7 a 1 and 6 a 1 ofthe region R1, and the first polymer portion 12 a may be removed fromthe inside of the hole patterns 7 a 2 and 6 a 2 of the region R2.

For example, by the RIE method and the like, the first polymer portion11 a and the first polymer portion 12 a may be etched in an etchingcondition that etch selectivity of the polystyrene (PS) with respect tothe hard mask 6 a (carbon) can be ensured. In this way, the firstpolymer portion 11 a may be removed from the inside of the hole patterns7 a 1 and 6 a 1 of the region R1, and the first polymer portion 12 a maybe removed from the inside of the hole patterns 7 a 2 and 6 a 2 of theregion R2. In the region R2, a part of the surface of the hard mask 4may be exposed as a bottom surface of the hole patterns 7 a 2 and 6 a 2.

In the process illustrated in FIG. 4B, in the region R1, the holepattern 5 b 1 may be transferred to the hard mask 4 a to form a holepattern 4 4 1, and in the region R2, the hole patterns 7 a 2 and 6 a 2may be transferred to the hard mask 4 a to form a hole pattern 4 a 2.

For example, by the RIE method and the like, the hard mask 4 may beetched. In this case, in the region R1, the hard mask 4 a maybe etchedusing the hard mask 5 b as a mask to form the hole pattern 4 4 1. Sincethe hard mask 5 b serves as an etching stopper, it is possible to formthe hole pattern 4 4 1 having a diameter smaller than that of thephysical guide (the hole pattern 6 a 1). In the region R2, the hard mask4 a may be etched using the hard mask 6 a as a mask to form the holepattern 4 a 2.

In this way, patterns (the hole pattern 4 4 1 and the hole pattern 4 a2) with different dimensions can be collectively formed in the hard mask4 a. For example, the hole pattern 4 4 1 of 25 nm can be formed in thehard mask 4 of the region R1 and the hole pattern 4 a 2 of 200 nm can beformed in the hard mask 4 of the region R2.

In the process illustrated in FIG. 5A, in the region R1, the holepattern 4 4 1 may be transferred to the hard mask 3 a to form a holepattern 3 a 1, and in the region R2, the hole pattern 4 a 2 may betransferred to the hard mask 3 a to form a hole pattern 3 a 2.

For example, by the RIE method and the like, the hard mask 3 a may beetched in an etching condition that etch selectivity of the hard mask 3(e.g., carbon) with respect to the hard mask 4 (e.g., silicon oxide) canbe ensured. In this case, in the region R1, the hard mask 3 a may beetched using the hard mask 5 b and the hard mask 4 a as a mask to formthe hole pattern 3 a 1. In the region R2, the hard mask 3 a may beetched using the hard mask 4 a as a mask to form the hole pattern 3 a 2.

In this way, patterns (e.g., the hole pattern 3 a 1 and the hole pattern3 a 2) with different dimensions can be collectively formed in the hardmask 3 a. For example, the hole pattern 3 a 1 of 25 nm can be formed inthe hard mask 3 a of the region R1 and the hole pattern 3 a 2 of 200 nmcan be formed in the hard mask 3 a of the region R2.

In the process illustrated in FIG. 5B, in the region R1, the holepattern 3 a 1 may be transferred to a processed film 2 a to form a holepattern 2 a 1, and in the region R2, the hole pattern 3 a 2 may betransferred to the processed film 2 a to form a hole pattern 2 a 2.

For example, by the RIE method and the like, the processed film 2 a maybe etched in an etching condition that etch selectivity of the processedfilm 2 a (e.g., silicon oxide) with respect to the hard mask 3 a (e.g.,carbon) can be ensured. In this case, in the region R1, the processedfilm 2 a may be etched using the hard mask 5 b, the hard mask 4 a, andthe hard mask 3 a as a mask to form the hole pattern 2 a 1. In theregion R2, the processed film 2 a may be etched using the hard mask 4 aand the hard mask 3 a as a mask to form the hole pattern 2 a 2.

In this way, patterns (e.g., the hole pattern 2 a 1 and the hole pattern2 a 2) with different dimensions can be collectively formed in theprocessed film 2 a. For example, the hole pattern 2 a 1 of 25 nm can beformed in the processed film 2 a of the region R1 and the hole pattern 2a 2 of 200 nm can be formed in the processed film 2 a of the region R2.

As described above, in some embodiments, the pattern formation using theself-organization lithography technology may be performed and a part ofthe physical guide may be used for the pattern formation as is. In thisway, it is possible to reduce the number of processes for formingpatterns with different dimensions. That is, it is possible toefficiently form patterns by using the self-organization lithographytechnology.

Furthermore, in some embodiments, the hard mask 5 a maybe selectivelyformed in the region R1, the hole pattern 11 c of the region R1developed with the self-organization lithography technology may betransferred to the hard mask 5 a, and it is possible that the dummy holepattern 12 c of the region R2 is not transferred to a lower layer. Inthis way, the hole pattern 5 b 1 of the region R1 and the hole pattern 6a 2 (e.g., the physical guide) of the region R2 can be collectivelytransferred to a lower layer film while using the hard mask 5 a as anetching stopper, so that it is possible to reduce the number ofprocesses required for forming patterns with different dimensions.

In some embodiments, instead of forming the dummy hole pattern 12 c inthe region R2 to prevent the dummy hole pattern 12 c from beingtransferred to a lower layer, the hole pattern 6 a 2 (the physicalguide) of the region R2 maybe covered with a resist pattern, so that ahole pattern by the self-organization lithography technology may beselectively transferred to a lower layer in the region R1.

Specifically, as illustrated in FIG. 6A to FIG. 10B, processes differentfrom the embodiment in the following point may be performed. FIG. 6A toFIG. 6C, FIG. 7A to FIG. 7C, FIG. 8A to FIG. 8C, FIG. 9A to FIG. 9C, andFIG. 10A and FIG. 10B are process sectional views illustrating a patternformation method according to some embodiments.

In the process illustrated in FIG. 6A, the processed film 2, the hardmask 3, the hard mask 4, the hard mask 6, and the antireflection film 7may be sequentially deposited on the substrate 1, and the resist patternRP2 similar to that of FIG. 2A may be formed.

In the process illustrated in FIG. 6B, similarly to the processillustrated in FIG. 2B, the hole patterns RP2 a and RP2 b in the resistpattern RP2 may be transferred to the antireflection film 7 a and thehard mask 6 a. The formed recess patterns (e.g., the hole patterns 7 a 1and 6 a 1 and the hole patterns 7 a 2 and 6 a 2) may serve as physicalguides of a self-organization pattern of a subsequent process.

In the process illustrated in FIG. 6C, a resist pattern RP3 forselectively covering the physical guides (e.g., the hole patterns 7 a 2and 6 a 2) of the region R2 may be formed.

In the process illustrated in FIG. 7A, a sidewall spacer film 8 may beformed by the ALD method and the like on the stacked body SLBa obtainedin the processes up to FIG. 6C. The sidewall spacer film 8, for example,may be formed with a material in which silicon oxide is a maincomponent. The sidewall spacer film 8 may be formed to cover the innerside surfaces of the hole patterns 7 a 1 and 6 a 1 of the region R1 andcover a bottom surface (e.g., a part of the surface of the hard mask 4exposed through the hole patterns 7 a 1 and 6 a 1) of the hole patterns7 a 1 and 6 a 1.

In the process illustrated in FIG. 7B, a self-organization material maybe embedded in the physical guides (the hole patterns 7 a 1 and 6 a 1)of the region R1. In this case, since the physical guides (the holepatterns 7 a 2 and 6 a 2) of the region R2 are covered with the resistpattern RP3, it is possible that the self-organization material is notembedded. That is, the block polymer film 11 may be embedded in the holepatterns 7 a 1 and 6 a 1, but it is possible that the block polymer film11 is not embedded in the hole patterns 7 a 2 and 6 a 2. Furthermore, athin film 22 of a block copolymer may be formed on the sidewall spacerfilm 8.

In the process illustrated in FIG. 7C, the stacked body SLBb obtained inthe processes up to FIG. 7B may be heated by a heating device, so thatthe block polymer film 11 is microphase-separated. When the stacked bodySLBb is heated on a hot plate at 240° C. for three minutes, the blockpolymer film 11 can be microphase-separated. That is, at the innersurface sides of the hole patterns 7 a 1 and 6 a 1, the first polymerportion 11 a including the PS is formed (e.g., segregated), and at thecenter sides of the hole patterns 7 a 1 and 6 a 1, the second polymerportion 11 b including the PMMA may be formed.

In the process illustrated in FIG. 8A, the hole pattern 11 c may bedeveloped in the hole patterns 7 a 1 and 6 a 1. For example, by the RIEmethod and the like, in the hole patterns 7 a 1 and 6 a 1, the firstpolymer portion 11 a may be allowed to remain and the second polymerportion 11 b may be selectively removed, so that the hole pattern 11 cis formed. In this case, a thin film 22 a corresponding to the secondpolymer portion can remain on the sidewall spacer film 8.

In the process illustrated in FIG. 8B, by the RIE method and the like,the thin film 22 a of the block copolymer remaining in the region R2 maybe removed. In the region R2, the sidewall spacer film 8 may be exposed.

In the process illustrated in FIG. 8C, in the region R1, the holepattern 11 c maybe transferred to a sidewall spacer film 8 a to form ahole pattern 8 a 1.

For example, in the region R1, the sidewall spacer film 8 a may beetched using the remaining first polymer portion 11 a as a mask by theRIE method and the like. A part of the surface of the sidewall spacerfilm 8 a exposed through the hole pattern 11 c may be selectivelyremoved and the hole pattern 11 c is transferred to the sidewall spacerfilm 8 a, so that the hole pattern 8 a 1 is formed. Apart of the surfaceof the hard mask 4 may be exposed through the hole pattern 8 a 1. In theregion R2, the physical guides (the hole patterns 7 a 2 and 6 a 2) maybe covered with the resist pattern RP3.

In the process illustrated in FIG. 9A, the first polymer portion 11 amay be removed from the inside of the hole patterns 7 a 1 and 6 a 1 ofthe region R1, and the resist pattern RP3 of the region R2 may beremoved.

In the process illustrated in FIG. 9B, in the region R1, the holepattern 8 a 1 may be transferred to the hard mask 4 a to form a holepattern 4 4 1, and in the region R2, the hole patterns 7 a 2 and 6 a 2may be transferred to the hard mask 4 a to form a hole pattern 4 a 2.

In the process illustrated in FIG. 9C, by the RIE method and the like,the sidewall spacer film 8 a and the antireflection film 7 a may beremoved.

In the process illustrated in FIG. 10A, in the region R1, the holepattern 4 4 1 may be transferred to the hard mask 3 a to form a holepattern 3 a 1, and in the region R2, the hole pattern 4 a 2 may betransferred to the hard mask 3 a to form a hole pattern 3 a 2. Then, inthe region R1, the hole pattern 3 a 1 may be transferred to theprocessed film 2 a to form a hole pattern 2 a 1, and in the region R2,the hole pattern 3 a 2 may be transferred to the processed film 2 a toform a hole pattern 2 a 2.

In the process illustrated in FIG. 10B, by the RIE method and the like,the hard mask 4 a and the hard mask 3 a may be removed.

In some embodiments, pattern formation using the self-organizationlithography technology may be performed and a part of the physical guidemay be used for the pattern formation as is. In this way, it is possibleto reduce the number of processes required for forming patterns withdifferent dimensions. That is, it is possible to efficiently formpatterns by using the self-organization lithography technology.

While certain embodiments have been described, these embodiments havebeen presented byway of example only, and are not intended to limit thescope of the disclosure. Indeed, the embodiments described herein may beembodied in a variety of other forms. Furthermore, various omissions,substitutions and changes in the form of the embodiments describedherein may be made without departing from the spirit of the disclosure.The accompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosure.

What is claimed is:
 1. A pattern formation method comprising: forming a first pattern in a first film in a first region and forming a second pattern in the first film in a second region by using optical lithography; forming a third pattern corresponding to the first pattern in a second film below the first film in the first region by using self-organization lithography; and transferring the third pattern to a third film below the first film and below the second film in the first region and transferring the second pattern to the third film in the second region.
 2. The pattern formation method according to claim 1, wherein the transferring of the third pattern and the transferring of the second pattern are collectively performed by etching using the third pattern and the second pattern as a mask.
 3. The pattern formation method according to claim 1, wherein the forming of the third pattern comprises: embedding a self-organization material in the first pattern and the second pattern and performing microphase separation; developing a fourth pattern in the first pattern and developing a dummy pattern in the second pattern; and transferring the fourth pattern to the second film to form the third pattern and without transferring the dummy pattern.
 4. The pattern formation method according to claim 1, wherein the forming of the third pattern comprises: forming a resist pattern for selectively covering the second pattern; embedding a self-organization material in the first pattern and performing microphase separation; developing a fourth pattern in the first pattern; transferring the fourth pattern to the second film to form the third pattern; and removing the resist pattern.
 5. The pattern formation method according to claim 1, wherein a maximum width of the first pattern is smaller than a maximum width of the second pattern, and a maximum width of the third pattern is smaller than the maximum width of the first pattern. 